Spherical objects, such as ball bearings, play an essential part in almost every mechanical operation. Superior bearings normally mean superior performance, with all its attendant advantages i.e. economy, efficient functioning etc. The more difficult task is the production of superior bearings. In order for the bearings to approach perfect spheres, environmental factors such as gravity must be minimized or overcome. Research has ranged from manufacturing operations in space in the absence of gravity to energy-intensive operations on earth using rotation and grinding to produce the sphere. Conventional grinding processes necessarily mean substantial material waste as the objects are ground into spherical form.
Examples of devices to manufacture spheres are found in U.S. Pat. Nos. 2,980,628 and 3,023,171 to Smith. These devices teach the manufacture of hydrogel spheroids of various composition, which material is dropped into an oil or gelling bath. The dropping tip or tips must be above the liquid level and the process is operated under superatmospheric pressure. The products float down through the bath and are collected out of the bottom of the device. Another example is found in U.S. Pat. No. 3,183,537 to Starr. The patent discloses a conduit for directing a stream of molten iron through the atmosphere and spraying the stream with hot water jets to break up the stream into globular granules.
Gravity and other factors affect both the shape and the density of bearings, both of which have a substantial effect on performance. Defects, however, are difficult to detect prior to actual failure since visual inspections provide little information. When actual failure does occur, the consequences may be both expensive and time consuming in terms of necessary repairs.